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Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during g
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap |
Date: |
Mon, 24 Jun 2019 10:43:21 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
On 24/06/19 10:06, Peter Xu wrote:
> Well, if with such an error we'd better fix it right away in this
> patch... :)
>
> Let me wait for some more comments, I'll touch that up too if I need a
> repost.
Looks good to me, except for one minor issue in this patch. But do not
attribute this one to me, it's basically all code from you.
> +static uint64_t vtd_get_next_mask(uint64_t start, uint64_t size, int gaw)
> +{
> + /* Tries to find smallest mask from start first */
> + uint64_t rmask = start & -start, max_mask = 1ULL << gaw;
> +
> + assert(size && gaw > 0 && gaw < 64);
> +
> + /* Zero start, or too big */
> + if (!rmask || rmask > max_mask) {
> + rmask = max_mask;
> + }
Perhaps simpler:
uint64_t max_mask = 1ULL << gaw;
uint64_t alignment = start ? start & -start : max_mask;
size = MIN(size, max_mask);
if (alignment <= size) {
/* Increase the alignment of start */
return alignment;
} else {
/* Find the largest page mask from size */
return 1ULL << (63 - clz64(size));
}
Also please rename it to get_naturally_aligned_size.
Paolo
- [Qemu-devel] [PATCH 0/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
- [Qemu-devel] [PATCH 1/2] intel_iommu: Fix incorrect "end" for vtd_address_space_unmap, Peter Xu, 2019/06/24
- [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Yan Zhao, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Yan Zhao, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Paolo Bonzini, 2019/06/24
- Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Peter Xu, 2019/06/24
Re: [Qemu-devel] [PATCH 2/2] intel_iommu: Fix unexpected unmaps during global unmap, Yan Zhao, 2019/06/24